• Harrop Engineering doing the "impossible" - Introducing the world's first positive displacement E92/E90/E92 S65 V8 supercharger

      Wow. That is exactly what came out of my mouth when I saw this supercharger kit at Bimmerfest. In all honesty, it was my main motivation for attending the event once I heard it would be there. Some people may be reading this and wondering what the big deal is as superchargers already exist for the M3. That is true, superchargers do exist, but they are all centrifugal style blowers. This is the world's first positive displacement supercharger for the S65 V8.

      Why is that a big deal? Because it's a completely different type of blower with completely different power delivery. This is the solution for those who complain about the M3's torque or for those who do not like the response down low of a centrifgual blower which needs rpm to make boost. This style of supercharger is always making boost, from anywhere in the rev range.

      That is what makes incorporating it on the S66 V8 difficult with its independent throttle bodies as positive displacement blowers usually are set to pull air through a throttle body not blow into it. The centrifugal blowers send air into a manifold. If a positive displacement were to use a similar setup it would be blowing air in while the throttle bodies attempted to close as it is always making boost. See the problem?

      The solution Harrop Engineering came up with was a manifold that fits in between the throttle bodies with a bypass valve fit that relieves pressure as needed and makes sure boost is not made as throttles are closing. Pretty trick setup eh? You can see the design in the photos and also how tight the packaging is. I do not even want to know how many hours were put in trying to get this all to fit.

      The blower employed is a TVS1740 unit from Eaton. This is a roots blower and likely will be set to 5.5 psi or so initially. Boost from this blower is different from a centrifugal and will be harder on the stock rods since it is at full boost right away. Expect horsepower in the low 500's to the wheels.

      Oh and see that little black box to the left of the manifold off a metal area at the inlet? There will be electronic boost control which is likely the first of its kind on a positive displacement setup although I am not able to confirm this. Different maps with different boost levels for different fuel? A possibility, yes.

      This is a big deal and an engineering feat for the S65. My complete and utter respect and that of this network to the guys at Harrop. There is still work to be done here. It is not quite ready although pricing is initially set at $12,990. There is still a lot of tuning to be done but this will be coming eventually.

      Pictures below, much respect Harrop and it was a pleasure meeting you guys at Bimmerfest. You were incredibly nice and answered all my (MANY) questions. Thank you:























      This article was originally published in forum thread: Harrop Engineering Twin Screw S65 V8 Supercharger started by CookieCrisp View original post
      Comments 276 Comments
      1. rooringhusky's Avatar
        rooringhusky -
        Anyone notice the flyer says the distribution partner is AVIVA....Funny bc they were supposedly making their own N54 single turbo kit as well....Even have a pic of the manifold on their website still I believe
      1. LostMarine's Avatar
        LostMarine -
        Click here to enlarge Originally Posted by mfatuation Click here to enlarge
        Stock DEM sir. Glad you like the car, I was guessing most people would hate on my wheel choice, but I really wanted to build something that I liked, not something that I knew everyone else would. I'll bring it out to a few shows for sure! Where in NJ are you?
        Build it the way you'll love it bro, $#@! everyone else
      1. benzy89's Avatar
        benzy89 -
        Click here to enlarge Originally Posted by mfatuation Click here to enlarge
        Stock DEM sir. Glad you like the car, I was guessing most people would hate on my wheel choice, but I really wanted to build something that I liked, not something that I knew everyone else would. I'll bring it out to a few shows for sure! Where in NJ are you?
        Haha it's def got the Subaru WRX STI vibe with the blue body/gold wheels contrast, but it looks awesome.. I'm North NJ (Morris County), but I adventure into South Jerz every so often
      1. DolphinM3's Avatar
        DolphinM3 -
        Click here to enlarge Originally Posted by rooringhusky Click here to enlarge
        Anyone notice the flyer says the distribution partner is AVIVA....Funny bc they were supposedly making their own N54 single turbo kit as well....Even have a pic of the manifold on their website still I believe
        Would love to see the flyer rooringhusky, do you still have it? Can you post it up?
      1. rooringhusky's Avatar
        rooringhusky -
        Click here to enlarge Originally Posted by DolphinM3 Click here to enlarge
        Would love to see the flyer rooringhusky, do you still have it? Can you post it up?
        Im on my phone right now and the bimmerboost site is a pain to use on mine...but go back to post #83 on this thread someone posted it up already! Hope that helps
      1. Sticky's Avatar
        Sticky -
        I've got a bunch of stuff sorry I didn't write the article yesterday guys ended up... well it was a good night.

        Anyway, working on it now.
      1. Sticky's Avatar
        Sticky -
        Wow. That is exactly what came out of my mouth when I saw this supercharger kit at Bimmerfest. In all honesty, it was my main motivation for attending the event once I heard it would be there. Some people may be reading this and wondering what the big deal is as superchargers already exist for the M3. That is true, superchargers do exist, but they are all centrifugal style blowers. This is the world's first positive displacement supercharger for the S65 V8.

        Why is that a big deal? Because it's a completely different type of blower with completely different power delivery. This is the solution for those who complain about the M3's torque or for those who do not like the response down low of a centrifgual blower which needs rpm to make boost. This style of supercharger is always making boost, from anywhere in the rev range.

        That is what makes incorporating it on the S66 V8 difficult with its independent throttle bodies as positive displacement blowers usually are set to pull air through a throttle body not blow into it. The centrifugal blowers send air into a manifold. If a positive displacement were to use a similar setup it would be blowing air in while the throttle bodies attempted to close as it is always making boost. See the problem?

        The solution Harrop Engineering came up with was a manifold that fits in between the throttle bodies with a bypass valve fit that relieves pressure as needed and makes sure boost is not made as throttles are closing. Pretty trick setup eh? You can see the design in the photos and also how tight the packaging is. I do not even want to know how many hours were put in trying to get this all to fit.

        The blower employed is a TVS1740 unit from Eaton. This is a roots blower and likely will be set to 5.5 psi or so initially. Boost from this blower is different from a centrifugal and will be harder on the stock rods since it is at full boost right away. Expect horsepower in the low 500's to the wheels.

        Oh and see that little black box to the left of the manifold off a metal area at the inlet? There will be electronic boost control which is likely the first of its kind on a positive displacement setup although I am not able to confirm this. Different maps with different boost levels for different fuel? A possibility, yes.

        This is a big deal and an engineering feat for the S65. My complete and utter respect and that of this network to the guys at Harrop. There is still work to be done here. It is not quite ready although pricing is initially set at $12,990. There is still a lot of tuning to be done but this will be coming eventually.

        Pictures below, much respect Harrop and it was a pleasure meeting you guys at Bimmerfest. You were incredibly nice and answered all my (MANY) questions. Thank you:

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      1. benzy89's Avatar
        benzy89 -
        Manifold pics are the best ones.... Does anybody know what would be the max boost/power this blower could turn out on the S65?? Including built motor potential.
      1. inlineS54B32's Avatar
        inlineS54B32 -
        Now I get it... To be honest, I didn't fully understand why this type of blower wasn't used. After reading the explanation, this makes a lot of sense why it wasn't done.

        I am guessing the car there is in a driveable state? Are these guys on the forum?

        Cheers.
      1. DFM's Avatar
        DFM -
        I was scratching my head quite a bit until I noticed the blower is inverted. Awesome setup, hat off to Harrop Engineering.
      1. Sered's Avatar
        Sered -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        It always makes boost. Meaning you get an instant torque increase at all rpm ranges. It's as if you increased the displacement of your motor.

        As far as negative it won't have the top end pull of a centrifugal and you can't go much bigger than this blower. Also, it's a roots blower meaning it will be best at low boost ranges as past a certain amount it loses efficiency compared to a twin screw.

        This will be an ideal stock internal setup.

        Yes, all the other kits will be faster on the top end but this will be much, much, MUCH more fun to drive.
        Positive displacement blowers also have more difficulty with heatsoak (the main reason the CTS-V and ZL1 suffer from it so badly -- though the ZR1 doesn't seem to have too much trouble). It will be interesting to see how the S65 performs.
      1. LostMarine's Avatar
        LostMarine -
        eh, they stole my idea:
        http://www.germanboost.com/showthrea...438#post247438
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by benzy89 Click here to enlarge
        Manifold pics are the best ones.... Does anybody know what would be the max boost/power this blower could turn out on the S65?? Including built motor potential.
        With a built motor it would be out of its efficiency range. As this is a roots style blower its best at low boost.

        With a built motor I don't think more than 6xx will be possible if that.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by Sered Click here to enlarge
        Positive displacement blowers also have more difficulty with heatsoak (the main reason the CTS-V and ZL1 suffer from it so badly -- though the ZR1 doesn't seem to have too much trouble). It will be interesting to see how the S65 performs.
        Very true although this is not pushing the blower super hard. But you raise a good point.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by inlineS54B32 Click here to enlarge
        Are these guys on the forum?
        Yes, they are.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by LostMarine Click here to enlarge
        It's the way they are bleeding off boost that makes this work.
      1. LostMarine's Avatar
        LostMarine -
        i really dont see more than 6 psi being used effectively. unless they have the E-valve to bleed boost, and even then i expect the tq to be a killer down low. man oh man if this works out though..
      1. LostMarine's Avatar
        LostMarine -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        It's the way they are bleeding off boost that makes this work.
        is it conformed the e- valve/bov?
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by LostMarine Click here to enlarge
        is it conformed the e- valve/bov?
        Yes, this was discussed.
      1. DFM's Avatar
        DFM -
        Maybe I missed it but what are they doing for cooling? or do we not know yet...